class_docstr: This context manager makes a wrapper of input_tensor
  When created, the input_tensor is dilated,
  the input_tensor resumes to original space when exiting the context.
code: def tensor(self):
      return self._tensor
  
file_path: NiftyNet/niftynet/layer/dilatedcontext.py
imports: from __future__ import absolute_import, print_function
  import tensorflow
  from niftynet.layer import layer_util
label_desc: Use image node_id 4 for calling the DilatedTensor obj's underlying member method code with example usage: obj.tensor() and returns: self